Nonce as uint256

[derekpierre]

Type of PR:

• Bugfix
• Feature
• Documentation
• Other

Required reviews:

• 1
• 2
• 3

What this does:

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Issues fixed/closed:

• Fixes #...

Why it's needed:

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[Copilot]

Pull Request Overview

This PR changes the nonce field type from u64 to Uint256 (a 256-bit unsigned integer) in the UserOperation and PackedUserOperation structures to support larger nonce values as required by the ERC-4337 standard.

Key changes:

• Introduces a new Uint256 wrapper type around primitive_types::U256 with serialization support
• Updates all UserOperation and PackedUserOperation structs to use Uint256 for nonce fields
• Adjusts language bindings (WASM and Python) to handle the larger integer type through string representations

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
nucypher-core/src/prim_types.rs	New module defining the Uint256 wrapper type with conversion and serialization methods
nucypher-core/src/lib.rs	Exports the new Uint256 type from the public API
nucypher-core/src/signature_request.rs	Updates UserOperation and PackedUserOperation structs to use Uint256 for nonce, changes JSON serialization to use decimal strings
nucypher-core/Cargo.toml	Adds primitive-types dependency with serde support
nucypher-core-wasm/src/lib.rs	Updates WASM bindings to accept/return nonce as string
nucypher-core-wasm/tests/wasm.rs	Updates tests to use string representation for nonce values
nucypher-core-python/src/lib.rs	Updates Python bindings to accept PyLong and return BigUint for nonce
nucypher-core-python/Cargo.toml	Adds num-bigint dependency and enables pyo3 num-bigint feature
Cargo.lock	Updates dependency tree with new crates

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.96%. Comparing base (806bc81) to head (82a8687).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #126      +/-   ##
==========================================
+ Coverage   63.51%   63.96%   +0.44%     
==========================================
  Files          20       21       +1     
  Lines        4498     4554      +56     
==========================================
+ Hits         2857     2913      +56     
  Misses       1641     1641              

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[cygnusv]

Would you consider to change this to to_big_endian_bytes?

[derekpierre]

I have no issue changing it at all.

For context, this is a common naming pattern in core Rust:

• https://doc.rust-lang.org/std/primitive.u32.html#method.to_be_bytes
• https://doc.rust-lang.org/std/primitive.u64.html#method.to_be_bytes
• https://doc.rust-lang.org/std/primitive.u128.html#method.to_be_bytes

and also followed by some of our existing code:

• https://github.com/nucypher/rust-umbral/blob/master/umbral-pre/src/keys.rs#L154
• https://github.com/nucypher/rust-umbral/blob/master/umbral-pre/src/keys.rs#L259

If this doesn’t change anything from your perspective, just say the word and I’ll update it.